Production of magnesium.



' STATES FATE? @EFECE i GEORGE O. SEWARD, 0F JERSEY CITY, NEW JERSEY, ASSIGNOR TO AMERICAN MAGNESIUM CORPORATION, A CORPORATION OF NEW YORK.

PRODUCTION OF MAGNESIUM.

To all whom it may concern:

Be it known that I, GEORGE O. SEWARD, a citizen of the United States, residing in Jersey City, county of Hudson, State of New Jersey, have invented certain new and useful Improvements in the Productionof Magnesium; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

In Letters Patent of the United States, No. 935,796, issued to Franz von Kugelgen and George 0. Seward, under date of October 5, 1909, is described a process for obtainirig magnesium, consisting in producing an alloy of magnesium with aluminum by electrolyzing a suitable electrolyte, com prising preferably magnesium chlorid together with potassium chlorid, and employing as a cathode molten aluminum; whereupon, the magnesium produced at the cathode combines with the molten aluminum to form a magnesium aluminum alloy. Thereafter, in a second step of the'operatiomthe magnesium aluminum alloy is used as an anode in a similar electrolyte to which has been added a certain proportion of a heavy salt of a metal more electro-positive than magnesium (as, for instance, barium chlorid) in order to increase the specific gravity of the electrolyte and thereby facilitate the flotation of the magnesium, the magnesium as it separates out from' the ,alloy being deposited at the cathode which is so located and arranged that the separated magnesium will float upon the electrolyte.

The present invention relates to an improvement upon the process described'in the patent referred to, andconsists primarily in substituting tin or copper for the aluminum employed as the cathode in the production of the magnesium alloy, and subsequently plating out the magnesium from the resultant magnesium-tin or magnesium-copper alloy.

In carrying the invention into practice, a suitable molten electrolyte such as magnesium chlorid and potassium chlorid, (MgCl :2KCl), may be employed, the electrolyte being subjected to the action of a continuous electric current, and with the employment of carbon anodes and a cathode of molten tin or molten copper.

Upon the passage of the current, the mag- Specification of Letters Patent.

Patented Mar. 5, i918.

' Application filed July 3, 1915. Serial No. 37,889.

nesium, produced at the molten tin or molten copper cathode, alloys therewith, the resultant alloy becoming richer in magnesium as the electrolysis proceeds. When the magnesium-tin or magnesium-copper alloy thus produced is sufiiciently rich in magnesium, it is removed, either in whole or in part, and is used as the anode in the second or plating out step of the process.

The electrolyte employed in the second step of the process is similar to that used in the first step. The specific gravity of the electrolyte, may, moreover, be increased by adding, as proposed in the patent hereinbefore referred to, a certain proportion of a heavy salt of a more electro-positive metal than magnesium (for instance, barium chlorid).

It will, of course, be understood, that as the magnesium separates out from the magnesium-tin or magnesium-copper anode it is deposited to the same" extent at the vcathode,

ess is that the resulting alloy of magnesium and tin or magnesium and copper is sufficiently heavy under all conditions of theelectrolysis. So also, magnesium is much more electro-positive with respect to tin and cop per than it is with respect to aluminum, and, for this reason, there is no danger of having any appreciable amount of the tinor the copper dissolve and thereafter plate out with the magnesium during the second step of the process. Furthermore, the refining of tin from silicon, iron, calcium and other impurities present in the electrolyte is effected with relative ease as compared with the refining of aluminum from the same impurities, and it is therefore entirely feasible to remove the impurities which remain in the tin after the plating out of the magnesium and to use the tin thus purified in the next succeeding operation. So also, traces of copper in a magnesium alloy are not prejudicial, for practically all of the uses for which magnesium is employed in the arts, and it is therefore of minor im-.

able electrolytic cells adapted for the practice of the invention, and it will be understood that cells of thi character may be employed, as shown therein, with the substitution of molten tin for molten aluminum in the firstLste of the process and the substitution of mo ten magnesium tin alloy in the second step of the process, and, also, with the substitution in both steps of the process, of the electrolytes hereinbe ore set forth. Having thus described my invention, what I claim is 1. The process of obtaining magnesium, which consists in electrolyzing a suitable ,magnesium-containing electrolyte with the employment of a molten cathode with respect to which magnesium is more electroposltlve'than 1t 1s with respect to aluminum,

and subsequently dissolving the magnesium out of said alloy by using the alloy as an. anode with a suitable molten electrolyte, and

depositing the magnesium at the cathode.

alloy as an anode with a suitable molten electrolyte and depositing the magnesium at the cathode.

In testimony whereof I afiix my signature.

GEORGE O. SEWARD. 

